Sciencemadness Discussion Board

synthesising pyrrole

bot402 - 3-8-2015 at 10:09

Is there a straightforward way of synthesising pyrrole?

I've scoured the internet and patents, but have come up with nothing that is as straightforward as, say Aniline synthesis, which, thanks to this forum is now a straightforward process, but I am in need of pyrrole and it's a devil to source and purchase in small quantities.

Many thanks in advance.


[Edited on 3-8-2015 by bot402]

kecskesajt - 3-8-2015 at 10:24

https://en.wikipedia.org/wiki/Pyrrole#Other_methods

gdflp - 3-8-2015 at 10:31

Check out Vogel in the forum library. A preparation of unsubstituted pyrrole from mucic acid can be found on page 837. Mucic acid isn't necessarily easy to come by, but a simple preparation by oxidizing lactose is found on page 453 in Vogel.

bot402 - 3-8-2015 at 11:10

Many thanks for that gdflp, I'll check it out over the next few days. I've seen references to mucic acid for pyrrole synthesis, but nothing as clear as the explanation you linked too (what a marvelous book!). Has anyone performed this synthesis? And if so, what were the results?

Thanks for the reply kecskesajit, but the wiki entry is rather vague for someone as inexperienced as myself.

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bobm4360 - 3-8-2015 at 21:35

http://www.orgsyn.org/demo.aspx?prep=CV1P0473

Org Syn isn't the answer to every need, but the procedures are tested by others before publication.

CuReUS - 4-8-2015 at 00:26

also see this,succinaldehyde isn't hard to get
https://en.wikipedia.org/wiki/Paal%E2%80%93Knorr_synthesis
Quote:
The reaction is typically run under protic or Lewis acidic conditions, with a primary amine. Use of ammonium hydroxide or ammonium acetate (as reported by Paal) gives the N-unsubstituted pyrrole.


[Edited on 4-8-2015 by CuReUS]

DJF90 - 4-8-2015 at 00:59

It has been done before, but not here (to the best of my memory):

http://www.lambdasyn.org/synfiles/schleimsaeure.htm

http://www.lambdasyn.org/synfiles/pyrrol.htm

bot402 - 4-8-2015 at 07:40

Many thanks for that DJF90. That's just what I was looking for, a step by step guide with chemical measurements etc.

Translation into English is a bit off, but all the essentials are there and I'll straighten out the translation by hand for easier reading.

Also thanks to bobm4360 for the other guide, again, a straightforward procedure.

Again, thank you, and all who replied to my thread. It never ceases to amaze me how knowledgeable some users of this forum are.

One final question. In your more knowledgeable opinions, could the initial pyrrole distillation (mucic and glycerole) be carried out in an autoclave based on a can and a pipe, as is done when extracting benzine from benzoic acid. This may save my flasks from breaking with the exposed heat of a burner. The extracted (impure) pyrrole could then be distilled in a more controlled and cleaner environment.

I'll report back when I've attempted the synthesis of both mucuc acid and pyrrole, and let you know how it goes.

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DJF90 - 4-8-2015 at 23:05

Quote: Originally posted by bot402  
One final question. In your more knowledgeable opinions, could the initial pyrrole distillation (mucic and glycerole) be carried out in an autoclave based on a can and a pipe, as is done when extracting benzine from benzoic acid. This may save my flasks from breaking with the exposed heat of a burner. The extracted (impure) pyrrole could then be distilled in a more controlled and cleaner environment.


What you describe is not an autoclave, but essentially a metal retort. It should be fine for the dry distillation of ammonium mucate. However, bear in mind the OrgSyn procedure uses glycerol as "solvent"/heat transfer medium, so if you intend to go this route it would be advantageous or perhaps even necessary to have good stirring in order to keep the mucate in suspension. The decomposition temperature of ammonium mucate is about 250 *C, so whilst a little high the glassware can stand it (especially with the glycerol present to help with heat transfer).